A research note on the occurrence of 'star' flowers in grapevines: Observations during the 2003-2004 growing season

In 2003 star flowers were observed on three different grape varieties in the Coombe Vineyard at the University of Adelaide's Waite Campus. The earliest star flowers on Canada Muscat, and those on Gamay (which were also associated with stunted shoots), most closely resembled the structure of star flowers as described by previous authors. Later in the season, despite opening in star formation, the organs of the star flowers were normal. Star flowers may take different forms, which in turn hold implications for their comparative ability to set fruit. In contrast to previously published reports, the subsequent occurrence of normal flowers on a double-pruned Canada Muscat vine demonstrated that star flowers are not necessarily expressed during each and every generation of flowers. Occurrence of star flowers probably results from a genotype X environment X time interaction rather than a developmental aberration that is expressed during each and every generation of flowers.